Sand trap for pump by-pass line to motor control switch diaphragm



1963 G. w. HUGHES SAND TRAP FOR PUMP BY-PASS LINE T0 MOTOR CONTROL SWITCH DIAPHRAGM Filed Dec. 11, 1961 I NVENTOR.

Geo/ye VV. Hay/2e;

United States Patent 3 114,320 SAND TRAP FQR PUM BYPASS LINE T0 MOTUR CONTROL SWETCH DHAPHRAGM George W. Hughes, 3405 Ennis St., Houston, Tex. Filed Dec. 11, 1961, Ser. No. 158,382 5 Claims. (Cl. 103-25) This invention relates to a combination reservoir, motor driven pump and a switch in circuit with the motor urged closed but normally held open by reservoir fluid pressure, the switch closing responsive to the decrease of pressure in the reservoir and against the switch. More particularly the invention relates to a switch, which up crates to start a motor which drives a pump when a decrease of pressure in a reservoir and against a diaphragm result in a stem connected to the diaphragm being depressed and urged by a spring to close the switch.

It is therefore a primary object of the invention to provide the combination of a reservoir, motor-driven pump, switch, and pressure responsive means to close a switch normally held open by fluid pressure responsive to the reduction of pressure in the reservoir, as by the fact that an outlet in the reservoir opened.

It is also another and important object of the invention to provide a combination reservoir, motor driven pump and switch of this class in which the means of applying pressure to the switch includes a sand trap in the bypass fluid pressure line whereby sand is trapped and not lodged beneath the diaphragm which normally holds the switch open whereby the switch may not close in an emergency.

It is also another and further object of the invention to provide a switch of this class, in combination with a motor driven pump, a reservoir and a bypass line in which the separation of sand from the means of applying pressure to the switch insures against the switch control being unable to close due to entrapment of sand thereunder.

Other and further objects will be apparent when the specification herein is considered in connection with the drawing in which the single FIGURE of the drawing shows the invention including motor driven pump, reservoir to which the fluid is supplied by the pump and the bypass line from pump to switch, sand-trap to which pres sure fluid is applied normally to maintain the switcn open.

Refering in detail to the drawing, a pump It is shown which draws fluid from a fluid source, as a well, through an inlet ii, and discharges the fluid through a discharge conduit 12 into a reservoir l3. An outlet line 12 .IODI the reservoir 13 is shown controlled by an ordinary stop valve 13'.

A discharge conduit 14 leads from the main discharge conduit 12 and includes a sandtr ap 15 therein which is comprised of an enlarged cylinder having upper and lower end closures 31 and 32 which are substantially larger than the bypass conduit 14 to provide ample area for sand entrapment.

A discharge nipple 16 connects the trap 35 to a diaphragm assembly 17 including its base plate 33. The body casting 34 of the diaphragm asscribly 17 includes a connecting flange 35 which mates with the outer flange of the base 33, the flange 35 and base 33 being connected by bolts and nuts 36.

A stem 2% is connected centrally to the diaphragm l8, and such stem extends through here 37' in the upper end of the body 34 to urge open a switch 21, which would be otherwise normally closed.

The switch 21 is in circuit in series with power line 22, comprising one of the electrical conductors which connects to the motor 24 which drives the pump it The other side of the power line comprises a conductor 23, which also extends from a source of power and is 3,114,326 Patented Dec. 17, 1963 "Ice connected to the motor 24 to comprise the second lead or conductor.

In operation, if the valve 13' is turned open, fluid runs from reservoir 13 out through conduit 12, whereby pressure is reduced in the conduit 12 and in the bypass conduit 14, so that the normally operative fluid pressure, which the pump has delivered to bear against the diaphragm 18, is reduced in value, and falls off in such degree that the diaphragm with the stem 20 attached thereto, may react responsive to the pressure of the spring 19 'thereabove. Thus the switch 21 is able to close as the stem 2% descends, responsive to such a decrease in pressure. When the switch 21 closes, circuit is cornpleted and the motor 24 is turned on to drive the pump it However, it often happens in operation with conventional equipment, that the bypass conduit '14 delivers sand with the pressured fluid to pass up into the diaphragm assembly 34, as indicated at 26. The result is, that the diaphragm 13 cannot descend any substantial amount, even though the valve 13' is open or turned on, so that there is a substantial decrease in the pressure in the reservoir l3 and in the bypass line 14. This results in a condition whereby the motor is maintained constantly turned off, and will not start to drive the pump no matter how much of the fluid in the reservoir 13 may run off or be drained from the reservoir through conduit 12'.

The invention as herein described, will prevent such an occurrence as this, since the pressure fluid through the conduit 114 is discharged to fill trap 15 before it fills the nipple l6, and bears against the diaphragm 18. Thus any sand that is carried from the well through pump 10 can precipitate into the area 27, indicated in the drawing to lodge in the sand trap 15'. Consequently, the diaphragm assembly =17 will not sand up and the stem 2t can be depressed to permit the switch 21 to close.

Also it is noticeable with this invention that when the stern 2d is de ressed responsive to a decrease in pressure there below, a washing action is set up in the chamber 15, whereby the back turbulent returns any sand entrapped in the cylinder 15 back into the bypass conduit l4, so that the pump may fully circulate it through the conduit 12 into the reservoir 13.

The invention is not limited to the exact disclosure shown, nor to the exact structural arrangement or elements, comprising the overall combination. Other variations, modifications and adaptations are included, as such carry out the function of preventing the accumulation of sand beneath the means which normally holds the switch open.

Thus any suitable type of sand trap and switch which will carry out the general purposes of the invention are included, and in fact the invent-ion is not limited by any structure except such structures as may fall within the broad spirit of the invention and within the broad scope of interpretations claimed for, and merited by the appended claims.

What is claimed is:

1. A device operable to tend to insure the operation of a fluid pressure diaphragm operated switch controlled, motor driven pump, having an inlet and a discharge connected to a closed container; a bypass line from pump discharge, a sand trap in said bypass line of larger diameter than said line to provide trap space within the base thereof, connection means at the top of said trap, a diaphragm housing containing a diaphragm thereacross and connected by said connection means to receive pressurized fluid as delivered by said pump through said sand trap to bear against the upstream side of said diaphragm, a plunger extending from downstream side of said diaphragm and out of said housing and to open said switch when urged by increased pressure of pump delivered fluid, said device mounting said diaphragm housing upwardly whereby sand delivered with fluid from said pump may be precipitated by gravity into said sand trap to insure the normal operating pressure position of said diaphragm maintains said plunger out of switch opening contact.

2. The combination as claimed in claim 1 in which sai sand tnap comprises a drum and said connection comprises a pipe of substantially smaller diameter than said drum.

3. The combination as claimed in claim 1 which includes a spring around said plunger between said diaphragm and said housing to urge said diaphragm out of switch opening position.

4. A sand trap protected, fluid actuated diaphragm operated device comprising a housing, a diaphragm thereacross, a plunger connected to the upper surface of said diaphragm and extending slidably through the top of said housing, a spring around said plunger between housing and diaphragm to urge said diaphragm downwardly, a drum having a bypass pipe extending dewnwardi from the lower end thereof, a connection pipe connecting the head of said drum to the bottom of said diaphragm housing, whereby when said by-pass pipe is connected into the discharge from a pump pumping sand bearing fluid to a closed container and said housing is mounted to position said plunger adjacent the normally closed switch which closes circuit to said pump, whereby send pumped with the discharge fluid is precipitated into the bottom of said drum instead of within said housing below said diaphragm, thus tending to insure that said plunger is not positioned to open said circuit until thus urged by increased pressure of pumped fluid.

5. The method of protecting a fluid actuated diaphragm plunger opened switch from being stuck in switch opened position comprising the steps of separating sand or depositable material pumped with the fluid actuating the diaphragm from the underside thereof to urge the plunger to switch opening position, whereby the switch opens only responsive to increased pump pressure as when the pump approaches filling a closed container.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A DEVICE OPERABLE TO TEND TO INSURE THE OPERATION OF A FLUID PRESSURE DIAPHRAGM OPERATED SWITCH CONTROLLED, MOTOR DRIVEN PUMP, HAVING AN INLET AND A DISCHARGE CONNECTED TO A CLOSED CONTAINER; A BYPASS LINE FROM PUMP DISCHARGE, A SAND TRAP IN SAID BYPASS LINE OF LARGER DIAMETER THAN SAID LINE TO PROVIDE TRAP SPACE WITHIN THE BASE THEREOF, CONNECTION MEANS AT THE TOP OF SAID TRAP, A DIAPHRAGM HOUSING CONTAINING A DIAPHRAGM THEREACROSS AND CONNECTED BY SAID CONNECTION MEANS TO RECEIVE PRESSURIZED FLUID AS DELIVERED BY SAID PUMP THROUGH SAID SAND TRAP TO BEAR AGAINST THE UPSTREAM SIDE OF SAID DIAPHRAGM, A PLUNGER EXTENDING FROM DOWNSTREAM SIDE OF SAID DIAPHRAGM AND OUT OF SAID HOUSING AND TO OPEN SAID SWITCH WHEN URGED BY INCREASED PRESSURE OF PUMP DELIVERED FLUID, SAID DEVICE MOUNTING SAID DIAPHRAGM HOUSING UPWARDLY WHEREBY SAND DELIVERED WITH FLUID FROM SAID PUMP MAY BE PRECIPITATED BY GRAVITY INTO SAID SAND TRAP TO INSURE THE NORMAL OPERATING PRESSURE POSITION OF SAID DIAPHRAGM MAINTAINS SAID PLUNGER OUT OF SWITCH OPENING CONTACT. 